Chinese economic reform and economic development proceed, the animal husbandry in our country has been rapidly developed, and the “shopping baskets” of residents have been greatly improved and the living standard of people has been increased. The animal husbandry in our country excellently contributes to agriculture and domestic economy: in 2010, the production of meats is 79.25 million tons and has been in the first place in the world for 21 years; the production of poultry eggs is 27.65 million tons and has been in the first place in the world for 26 years; and the production of milks is 37.80 million tons and is in the third place in the world. With rapid development of animal husbandry, the environment of urban areas and the ecological environment of rural areas encounter great stress, and the pollution caused by the livestock and poultry breeding is more and more severe. Therefore, it has been a significant and urgent task for rural environmental protection to enhance pollution control and environmental management of livestock and poultry breeding.
By taking Jiaxing city, Zhejiang province as an example, Jiaxing city lies in the center of Changjiang River Delta, and is near to Suzhou, Hangzhou, Shanghai, on the north, the south, and the east, respectively. Pig breeding has been developed since early 1990s, and nearby markets are mainly supplied. As a conventional intensive pig breeding region, the number of pig breeding units in the entire Jiaxing city has exceeded 100 thousand, and the number of fully grown pigs per year is 4.5 million. Under the conditions of extensive and intensive feeding, high death rate of pigs is unavoidable. In general, the death rate of adult sows per year is up to 2%-3%, the death rate of middle-age pigs is up to 7%-8%, and the death rate of piglets is even higher. According to local reports of special topics by CCTV, the average total death rate, from the time when a piglet is born to the time when it is fully grown, is 10%. Based on the calculation according to the data described above, the number of dead pigs for various reasons in Jiaxing area per year is up to hundreds of thousands. A large number of dead-of-disease livestock are not subjected to harmlessness treatment every year and some are even discarded into rivers, which does not only severely pollute the environment but also propagates fatal animal diseases, such as foot-and-mouth disease, highly pathogenic avian influenza, highly pathogenic blue-ear pig disease, and swine fever.
Municipal domestic refuse is solid waste produced in human life. In the process of collection, transportation and treatment, harmful components contained in and produced from the refuse will pollute the atmosphere, the soil, bodies of water. This does not only severely affect the quality of the municipal environment but also threatens health of people, and thus it becomes one of social public hazards. The annual production of municipal refuse per capita in China is up to 440 kilograms. In 1996, the amount of cleaned and transported municipal domestic refuse in China is up to 100 million tons, and increases at a rate of 8% to 10% per year. The amount of stockpiled municipal refuse in past years is up to 6 billion tons, and more than 200 cities in the whole country are surrounded by refuse. The stockpiled refuse occupies a land area of up to 500 million square meters. How to solve the problem of municipal refuse to provide a healthy and clean living environment to urban and rural residents has been highly focused in the whole society.
At present, organic refuse, such as dead-of-disease livestock and municipal refuse, are treated by incineration in many places. The process of incineration treatment does not only generate hydrogen sulfide (odor) which pollutes air, but also emits a number of toxic and harmful substances such as dioxin, nitrogen oxides, and sulfur dioxide, which affect health of residents nearby. The main reason why the above organic refuse such as dead-of-disease livestock and municipal refuse generates toxic and harmful substances, such as hydrogen sulfide (odor), dioxin, nitrogen oxides and sulfur dioxide, is the pyrolysis (combustion) treatment performed in an aerobic state. In dead-of-disease livestock and municipal refuse, ammonia nitrogen generates nitrogen oxides by the pyrolysis (combustion) in an aerobic state; sulfur generates sulfur dioxide by the pyrolysis (combustion) in an aerobic state; chloride ions generate dioxin by the pyrolysis (combustion) in an aerobic state; and carbon generates carbon dioxide and the like by the pyrolysis (combustion) in an aerobic state.
An anaerobic pyrolysis method and device for pyrolyzing organic refuse such as dead-of-disease livestock and municipal refuse in an anaerobic state, so as to solve the problems of reutilization and harmlessness treatment of organic refuse such as dead-of-disease livestock and municipal refuse generated during production and living of human beings and to prevent the generation of toxic and harmful substances such as hydrogen sulfide (odor), dioxin, nitrogen oxides and sulfur dioxide, has not been reported so far.